Automatic Discovery of Physical Topology in Ethernet Networks

Ethernet is becoming increasingly popular in metro and access networks due to the high bandwidth available at low cost. Nonetheless, native Ethernet lacks some features that are important for sophisticated network management; providing accurate knowledge on the physical topology is one of them. Therefore, automatic physical topology discovery in support of network management is essential in Ethernet networks. Former work either focused on Layer-3 topology discovery or only provided the active topology excluding the physical links inactivated by rapid spanning tree protocol. This paper introduces a novel mechanism capable of automatically discovering the entire physical topology of Ethernet networks. Our algorithm collects information available even in low-cost off- the-shelf Ethernet switches and then calculates the physical topology of the entire network. This paper describes the method and its implementation in a testbed network for assessing the performance and the robustness of the mechanism.